.van-doc-header {
  position: fixed;
  background: #fff;
  top: 0;
  z-index: 2;
}
.van-doc-footer {
  position: relative
}
.doc-body {
  margin: 60px auto !important;
  min-height: 100vh;
}
.side-menus {
  position: fixed;
  height: calc(100vh - 120px);
  overflow: auto;
}
.demo-view-qrcode {
  position: fixed;
  top: 80px;
  right: 20px;
  padding: 10px;
  border-radius: 5px;
  text-align: center;
  color: #999;
}
.demo-view-qrcode img {
  width: 160px;
  height: 160px;
  margin-bottom: 10px;
}